Scientists at DESY have made iron transparent.
Well, let's back up a moment.
DESY is the Deutsches Elektronen Synchrotron, or "German Electron Synchrotron", the biggest German research center for particle physics. What they have been working on there is making atomic nuclei transparent with the help of X-ray light. At the same time they have also discovered a new way to realize an optically controlled light switch that can be used to manipulate light with light, an important ingredient for efficient future quantum computers.
Wait a minute. Transparent iron? Quantum computers?
This look alike a good place for this…
The method these scientists used is known as electromagnetically induced transparency (EIT). The effect of EIT is well known from laser physics. With intense laser light of a certain wavelength it is possible to make a non-transparent material transparent for light of another wavelength. This team managed to prove for the first time that this transparency effect also exists for X-ray light, when the X-rays are directed towards atomic nuclei of the Mössbauer isotope iron-57 (which makes up 2% of naturally occurring iron). Quite remarkably, only very low light intensities are needed to observe this effect, in contrast to standard EIT experiments.
This experiment definitely means considerable technical progress for quantum computing: apart from the basic possibility to make materials transparent with light, the intensity of light is decisive for a future technical realization as well. Every additional quantum of light produces additional waste heat; this would be reduced by the use of the presently discovered effect.
The experiments of the DESY scientists also showed another parallel to the EIT effect: the light trapped in the optical cavity only travels with the speed of a few metres per second – normally it is nearly 300 000 kilometers per second. With further experiments, the scientists will clarify how slow the light really becomes under these circumstances, and whether it is possible to use this effect scientifically. A possible application and at the same time an important building block on the way to light-quantum computers is, for example, the storage of information with extremely slow or even stopped light pulses.